Learning by Accident
Excerpt from Crucible, September 2004.
««« Submitted by STAO Members in Region 3 and 4.
Learning by Accident is an ongoing Crucible feature, in which real-life
lab accidents or incidents are recounted and explained. The goal is to highlight
the consequence of ignoring safety rules so that science educators will
be further encouraged to become knowledgeable, and to take appropriate action,
in areas of safety that affect their daily activities in the science classroom.
Submissions are encouraged. If requested, anonymity will be guaranteed.
Please send written descriptions to Ian Mackellar, STAO Safety Committee
Past-Chair, Box 191, MAITLAND, ON K0E 1P0
A Purple Problem: Safe Waste Disposal from School Science Laboratories
A school custodian, collecting waste materials to be taken to the local
landfill site, started a fire when he added some broken glass from a ‘Broken
Glass’ container to the regular garbage which contained paper towels
and some unused potassium permanganate crystals from a recent student
activity. The broken glass was from a flask which had originally contained
Comments from the STAO Safety Committee
The spontaneous combustion of glycerol (flammable) in the presence of
potassium permanganate (strong oxidizing agent) should not surprise most
science teachers. Accordingly, this incident emphasizes the importance
of rendering hazardouschemicals safe before leaving for disposal. Whenever
possible, large pieces of broken laboratory glassware should be rinsed
with a surfactant solution to remove traces of the contents before they
are placed in the ‘Broken Glass’ container. Under no circumstances
should oxidizing agents be placed in the regular waste container. Any
excess permanganates from student experiments, as they contain a heavy
metal, should be stored for disposal by a licensed contractor . (See STAO
publication Stay Safe! for further guidance with respect disposal of hazardous